The objections I hear most often from the front lines of large companies:

1. Not a priority; they have too much else going on2. No internal owner to manage the projects and/or startups3. Needs are too proprietary to have external discussions4. We’re happy with our current suppliers/vendors
5. We do our own outreach (this answer is incredibly popular in Silicon Valley)

My response to these objections:

1. Not a priority – it will be, you may want to at least know who’s going to eat your lunch next year2. No owner – it depends on the company, but usually every organization has a few entrepreneurial/intrapreneurial people who would love to own these projects3. Too proprietary – even Apple lists job openings for automotive industry experts. There is no need to be specific, let the startups come to you with solutions4. Happy with suppliers – hmm…I was happy with over-the-air tv until I saw cable. I was happy with standard definition until I saw high definition and so on…5. Own outreach – in the HR world, do big companies only list their jobs on their own sites? Sure if they want 4 resumes, but if they want 400, they go to where the job seekers are like indeed, Linkedin, Monster. Go to where the startups are…